The best replacement for carboxylic acid is ester.

The best alternatives to carboxylic acid are rated as following:
★★★★★  ester
★★★★  alcohol boiling point
★★★  aldehyde
★★★  acetic acid
★★  percarboxylic acid
★★  ester polarity
★★  alcohol more polar
★★  alcohol higher boiling point
★★  ketone
★  ester more polar

Your alternative for carboxylic acid is not listed? Suggest!
Speaking about carboxylic acid, one probably shouldn't forget about socl2.

Other search terms related to carboxylic acid and their ratings are:
★★★★★ socl2
★★★★★ naoh
★★★ grignard
★★★ amine
★★ h2so4
★★ lah
★★ lioh
★ lialh4
★ thionyl chloride
★ sodium bicarbonate
benzene
pbr3
an alcohol
aldehyde
nahco3
You have in mind a companion for carboxylic acid and it is not yet here? Propose!



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carboxylic acid
ester
alcohol boiling point